Microsoft SwiftKey Keyboard for Android has the 'Auto Space' feature. By default, the 'Auto Space' option is enabled on your Microsoft Swiftkey keyboard, which automatically adds space when you type standard punctuation, this includes the comma, period, exclamation, question mark.
If you'd like to turn this off please follow the below steps.
Open the Microsoft SwiftKey app setting
Uncheck 'Auto Space'
For more help, Contact Support at Microsoft SwiftKey Support - Contact us